Nebulizer gas scavenger system with medication recycling and consumption metering

ABSTRACT

The nebulizer gas scavenging system includes a condenser positioned in the expiratory pathway of the breathing circuit for extracting liquid from expiratory gases and redirecting the extracting liquid to the input of the nebulizer. The system is further configured to detect the actual consumption of inhaled medication by measuring the concentration of medication in the expiratory pathway and comparing it to the initial content of medication in the aerosol of the inspiratory pathway. A more accurate determination of the amount of inhaled medication is advantageous in certain critical situations involving application of medication by inhalation.

BACKGROUND

Without limiting the scope of the invention, its background is describedin connection with nebulizers. More particularly, the inventiondescribes a system for detecting and measuring drug consumption when thenebulized aerosol is inhaled by the patient, as well as extracting thedrug from the exhalation pathway and re-directing it back to theinhalation pathway to increase drug consumption by the patient.

Medication delivery through inhalation by a patient is generally wellknown and used in a variety of circumstances. In particular, pulmonarytreatments, such as inhalation of albuterol, are frequently prescribedfor patients to apply at home. Inhalation delivery route is also usedduring surgery when the patient is subjected to anesthesia, as well asin certain dental procedures.

In a typical scenario, a facemask, a nasal cannula, a mouthpiece, or aface hood is positioned next to the patient's face so as to control theinspiratory flow and the expiratory flow in and out of the patient. Asource of desired medication, such as an inhalation drug or ananesthetic in some examples, is used to create a flow of gas desired tobe inhaled by the patient. The flow of gas is then directed to thefacemask and from there it is inhaled by the voluntary action of thelungs or injected by the machine under controlled conditions.

Exhaled gases are directed outwards and away from the face of thepatient in the expiratory pathway. These exhaled gases may be filteredor otherwise processed before releasing into the ambient environment.

Medical nebulizers for aerosolizing a liquid medication that can beinhaled by a patient are well-known devices commonly used for thetreatment of certain conditions and diseases. Nebulizers haveapplications in treatments for conscious, spontaneously-breathingpatients and for controlled ventilated patients.

Expiratory gas scavenging also is known in broad terms to be used forthe retrieval of volatile gas agents that may be toxic or undesirable ifreleased in the same room. These gases are typically filtered out orotherwise removed from the expiratory pathway by various means. It hasbeen long recognized that salvaging these gases and recycling them backinto the inhalation pathway may provide significant benefits, such asreduction of environmental harm, saving cost, and protecting medicalpersonnel surrounding the patient, to name a few. However, no suchpractical system has been developed so far despite multiple attemptsdescribed in the prior art.

Redirecting medication from the expiratory pathway back into the patientinput side of the breathing circuit may also be desirable when expensivemedication is used. Any portion of the medication that is exhaled by thepatient may be considered wasted and not properly consumed by thepatient. A need is therefore to increase the consumption of medicationby the patient in order to maximize the medication benefit and minimizethe amount of medication used during the procedure.

Another drawback of the present systems is the lack of precise controlas to how much of the medication inhaled by the patient is actuallyconsumed versus how much of it is exhaled and therefore not absorbed bythe patient's lungs. This is most important for the most critically illpatients, where exact knowledge of medication consumption is needed forthe best patient care. Some examples of the most critical circumstancesrequiring close control of the amount of inhaled and consumed medicationinclude (i) ribavirin treatment for RSV infections in neonates, (ii)acute exacerbations of asthma where nebulized albuterol is key totreatment of this condition, and (iii) acute exacerbations of COPD wherenebulized medication is a key component to therapy.

The need to recycle the active medication has to be balanced with theneed to sterilize the exhaled gases and remove harmful pathogens priorto reintroduction to the patient. This will avoid a risk ofcontamination of subsequent patients in case the same machine is usedfor more than one patient. The need exists therefore for a breathingsystem capable of measuring medication consumption more accurately aswell as recycling active medication from the expiratory pathways andredirecting it for further inhalation by the patient.

SUMMARY

Accordingly, it is an object of the present invention to overcome theseand other drawbacks of the prior art by providing a novel nebulizer gasscavenging system configured to extract and measure the liquid from theexpiratory pathway of the breathing circuit.

It is another object of the present invention to provide a novelnebulizer gas scavenging system capable of redirecting at least aportion of the medication exhaled by the patient back into the breathingcircuit, thereby improving overall consumption of the medication by thepatient.

It is a further object of the present invention to provide a novelnebulizer gas scavenging system configured to minimize the content ofmedication in the exhaust gases released into the ambient environmentfrom the expiratory pathway of the breathing circuit.

It is a further yet object of the present invention to provide a novelnebulizer gas scavenging system capable of isolating and retaining theliquid extracted from the expiratory gases so it can be properlydiscarded or further analyzed if needed.

The nebulizer gas scavenging system generally includes an inspiratorypathway leading to a facemask, and an expiratory pathway leading fromthe facemask. The facemask may be equipped with an inlet one-way valveand an outlet one-way valve to separate the inhalation aerosol from theexhalation gases.

The inspiratory pathway may feature a nebulizer with an input for amedical liquid. The nebulizer is designed to convert the medical liquidcoming in from the input thereof to an aerosol suitable for inhalationby the patient. The nebulizer may also be used to supply medicatedaerosol through the inspiratory pathway to the facemask.

The expiratory pathway features a condenser configured to extract liquidfrom expiratory gases originating at the facemask. After passing througha liquid container, the expiratory pathway is further configured toperform at least one of the following actions with the extracted liquid:

-   -   (i) sequester the fluid for subsequent disposal or further        analysis,    -   (ii) determine at least one parameter of the extracted liquid,        such as extracted volume or weight per unit time, or    -   (iii) direct the extracted liquid to the input of the nebulizer        to increase medication utilization and reducing the overall        amount of medication needed for the treatment.

Extracted liquid may be sent to be analyzed for further laboratoryevaluation or cultured for presence of bacteria or other pathogens.

The expiratory gas may be further filtered after exiting the condenserand then released to the ambient environment.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter is particularly pointed out and distinctly claimed in theconcluding portion of the specification. The foregoing and otherfeatures of the present disclosure will become more fully apparent fromthe following description and appended claims, taken in conjunction withthe accompanying drawings. Understanding that these drawings depict onlyseveral embodiments in accordance with the disclosure and are,therefore, not to be considered limiting of its scope, the disclosurewill be described with additional specificity and detail through the useof the accompanying drawings, in which:

FIG. 1 is a block diagram of the components forming a breathing circuitof the present invention;

FIG. 2 is the same but with the addition of an air pump;

FIG. 3 is the same as in FIG. 2 but with the addition of one or morehumidity sensors.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The following description sets forth various examples along withspecific details to provide a thorough understanding of claimed subjectmatter. It will be understood by those skilled in the art, however, thatclaimed subject matter may be practiced without one or more of thespecific details disclosed herein. Further, in some circumstances,well-known methods, procedures, systems, components and/or circuits havenot been described in detail in order to avoid unnecessarily obscuringclaimed subject matter. In the following detailed description, referenceis made to the accompanying drawings, which form a part hereof. In thedrawings, similar symbols typically identify similar components, unlesscontext dictates otherwise. The illustrative embodiments described inthe detailed description, drawings, and claims are not meant to belimiting. Other embodiments may be utilized, and other changes may bemade, without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and make part of this disclosure.

FIG. 1 shows a block diagram of an exemplary configuration of thenebulizer gas scavenger system 100 of the present invention showing afull breathing circuit with an inspiratory pathway and an expiratorypathway as its main components. The desired liquid medication may bedispersed into an aerosol by a nebulizer 110, supplied to a facemask 130next to the face of the patient via an inspiratory pathway tubing 120,then directed via an expiratory pathway tubing 140 to a condenser 150,where the liquid phase may be separated from the exhaled expiratorygases. The expiratory gases are then released to the ambient environmentafter passing through a filter 160. The condensed extracted liquid maybe collected, optionally filtered, separated by composition (i.e., watervs nebulized medication), measured, disinfected, and/or furtherconcentrated, and then redirected to the inlet of the nebulizer 110,thereby completing the circuit. In other embodiments, the extractedliquid may be sequestered and optionally further analyzed for contentand presence of bacteria or other pathogens.

The nebulizer 110 of the system is configured to disperse the desiredmedication and form an aerosol to allow the patient to breathe in theliquid medication containing thereof. The liquid medication is firstloaded into the input of the nebulizer before operating thereof. Thenebulizer 110 may be a standalone component or can be combined orconsolidated with one or more of the other components of the system asthe invention is not limited in this regard. The nebulizer 110 may beconfigured for use at home or in a hospital setting.

Various types of nebulizers may be used for the purposes of the presentinvention, including the most widely used jet or ultrasonic nebulizers.In a jet nebulizer, a jet of compressed air is used to create liquiddroplets, while in ultrasonic nebulizers, this is achieved by avibratory motion of an ultrasonic crystal. A broad discussion ofnebulizers may be found in a review (P. P. H. Le Brun, A. H. de Boer, H.G. M. Heijerman and H. W. Frijlink. A review of the technical aspects ofdrug nebulization. Pharm World Sci 2000; 22(3): 75-81), which isincorporated herein by reference. Droplet size and other key parametersof operation may be selected based on both patient and specific liquidmedication considerations. The liquid medication is supplied to thenebulizer from the input, such as a liquid container, as is wellunderstood by those skilled in the art, which is not shown on thedrawing.

Most nebulizers are still deficient in that it is difficult to meterexactly how much liquid medication is dispersed, as well as how muchmedication is actually consumed by the patient. A switch to dry powderinhalers may allow for better control of medication consumption, whichis a large part of the rationale to switch to dry inhalers. However,many liquid medications are not available in a dry powder form whichnecessitates continuous use of nebulizers in modern medical practice, orthe patient is unable to use such an inhaler due to a lack ofinspiratory effort ability or coordination/cognitive ability to properlyinterface with the inhaler. For the purposes of this disclosure, theterm “medical liquid” is used to refer to various types of saline,including various concentrations of hypotonic saline, isotonic saline,and hypertonic saline, salt water, distilled water, prescriptionmedications in liquid form, as well as supplement and recreationalliquids designed for inhalation, such as CBD/THC products, etc.

The inspiratory pathway 120 may include a simple tubing of sufficientlength to connect the nebulizer 110 to the facemask 130. The term“facemask” is used herein to broadly describe all patient interfacedevices located at or near the face of the patient and configured topreferentially provide the gas flow from the inspiratory pathway 120 forthe patient to breath in, while limiting breathing in of room air fromthe surrounding environment. Examples of what is included in the meaningof this term for the purposes of this disclosure include facemasks,nasal cannulas, intubation tubes and cannulas, mouthpieces, hoods, faceshields, etc. Some suitable examples of the facemask may be found in thearticle by Arzu Ari, Armele Dornelas de Andrade, Meryl Sheard, BshayerAlHamad, and James B. Fink. Performance Comparisons of Jet and MeshNebulizers Using Different Interfaces in Simulated SpontaneouslyBreathing Adults and Children. J OF AEROSOL MEDICINE AND PULMONARY DRUGDELIVERY, Vol. 28, No. 4, 2015, incorporated herein by reference.

The facemask 130 may be equipped with an inlet for connecting theinspiratory pathway 120 thereto. The inlet may be further equipped withan inlet one-way valve so as to assure the direction of flow only fromthe nebulizer 110 towards the patient as shown by an arrow in FIG. 1 .

Expiratory pathway 140 may be provided with sufficient length anddiameter to direct at least a sufficiently large portion or in somecases the entirety of the exhalation volume of gas away from the patientand towards the condenser 150. The facemask 130 may have an outlet towhich the expiratory pathway 140 may be attached. A second one-way valvemay also be provided as part of the facemask 130 or as part of theexpiratory pathway 140 and arranged to allow the flow of gases in adirection of the arrow in FIG. 1 and not in the opposite direction—so asto facilitate removal of exhaled expiratory gases from the patient andprevent mixing of the inhalation and exhalation gases.

As may be appreciated by those skilled in the art, at least some or allof the components exposed by the gases inhaled and exhaled by thepatient may be made disposable, especially the inspiratory pathway 120,expiratory pathway 140, and the facemask 130.

Condenser 150 may also be provided as part of the breathing circuit ofthe present invention. The objective of this component is to extractfluids from the high-humidity gas flow exiting the patient. Thecondenser may be operated using various techniques designed to extractmoisture from humid gas. One advantageous technique is to form a coldspot along the pathway of the gas so as to cause condensation of fluidsdue to the reduction of gas temperature. Desiccants, meshes, baffles,vanes, other gas dehydration, droplet extraction and concentrationtechnologies may also be used for that purpose as the invention is notlimited in this regard.

To maximize the efficiency of the condenser, the expiratory gas from thefacemask may be directed over through a serpentine or other indirect orconvoluted pathway wherein the walls forming the pathway may be madefrom a head-conductive material, such as metal. Alternatively, the flowof gas may be purposefully slowed down and cooled to permitcondensation. A cooling source, for example, may be provided to activelycool the walls of the condenser—such active cooling may be provided atleast in one location or throughout the entire length of the convolutedgas pathway of the condenser. In some embodiments, a thermoelectriccooler using a Peltier effect may be deployed. In broad terms,thermoelectric cooling uses the Peltier effect to create a heat flux atthe junction of two different types of materials. A Peltier cooler, alsoknown as a thermoelectric heat pump, is a solid-state active heat pumpthat transfers heat from one side of the device to the other, withconsumption of electrical energy, depending on the direction of thecurrent.

While the cooling side of the thermoelectric cooler may be thermallycoupled and used to operate the condenser 150, the heater side of thatdevice may be used to warm up the liquid medication prior to or as apart of the nebulizer 110. This is especially beneficial when the entiresystem is designed as a stand-alone, self-contained device. Heating upthe medical liquid from room temperature to at least body temperature oreven to somewhat higher temperatures may be used to maximize saturationof the inspiratory gas flow with the desired medication and increasepatient comfort.

The condenser 150 may be configured to direct drained liquid dropletsthat form along the serpentine pathway down to the bottom fluid trap ofthe device. This may allow the fluid to transport by a natural (bygravity) or an actively managed flow from the condenser 150 to theliquid container 180 via a drain pathway 170. The extracted liquid maybe sequestered and prepared for proper disposal. In other embodiments,the extracted liquid may undergo additional laboratory analysis or besubjected to a test for cultured bacteria or other pathogens.

The liquid container 180 may be physically located below the condenser150 to facilitate passive, gravity-controlled liquid drainage. Tofurther facilitate the drainage of the liquid drops away from the wallsof the condenser 150, it may be equipped with a device causing the wallsto periodically or continuously vibrate via an electrically-activatedvibration element, thereby causing the coalescence of smaller drops intolarger drops and forming streams of fluid inside the condenser. Thispromotes liquid drainage from the condenser 150. The vibration elementmay be coupled to the wall of the convoluted pathway and include arotating off-center mass or a piezoelectric element configured to applyvibrations thereto. The metal or other portions of the internalserpentine pathway or the entire breathing circuit may be made removableand detachable from each other so as to facilitate their cleaning andsterilization, such as by an autoclave, STERRAD, or an ethylene oxide,which can be done between patients to prevent cross-contamination.

In further embodiments, the condenser 150 may be configured to allow notone but multiple passes of the expiratory gases over the cold elementsthereof so as to further improve the efficiency of liquid extraction.

The flow of expiratory gas after passing through the condenser 150 maybe directed to a filter 160, such as a HEPA filter, a UV light, oranother suitable filtration, disinfection, and/or adsorption deviceconfigured to remove harmful pathogens such as viruses and bacteria fromthe expiratory pathway 140. After disinfecting the gas flow in thefilter 160, it may be released into ambient environment or exhaustedinto a dedicated circuit.

In further embodiments, a hospital vacuum system may be used in place ofthe exhaust fan to create the necessary pressure gradient, promote theflow of expiratory gases through the expiratory pathway 140 and safelyremove all gases from the breathing circuit.

Liquid container 180 may be configured to provide a variety ofadditional functions. First, liquid metering may be provided as afunction of time, which may be instrumental to determine the overallmedication consumption by the patient. Liquid metering may beaccomplished by including a weight measuring device configured to weighincoming fluids. Liquid metering may also be accomplished by volumemeasurements, density measurements, or subjected to further spectralanalysis.

Second, the liquid may be disinfected or decontaminated beforeredirecting thereof towards the nebulizer 110. This may be done byfiltering or using other disinfection means, for example by exposing thepassing liquid to a sufficient dose of UV light so as to cause thedestruction of bacteria, viruses, and other harmful pathogens. To assurethe safety of people around the machine, a disinfection chamber may belocated inside the device and be covered by an opaque material on allsides so as to preclude exposure of humans to the UV light of abroad-spectrum wavelength or a particular wavelength targeted at aspecific group of pathogens or bacteria. One example of a usefulspecific wavelength range is a so-called UVC range of frequencies ofabout 165-180 nm designed to disrupt DNA or RNA structure of bacteria orvirus. Selection and operation principled of bactericidal UV lights arewell known in the art to cause sufficient disinfection of the fluid,which is expected to be naturally transparent to allow deeperpenetration of UV rays therein.

As a further additional function of the liquid container 180, waterremoval and increase in the concentration of the liquid medication maybe further provided. This may be accomplished by centrifugation, waterevaporation, selective filtering, or using other known techniques as theinvention is not limited in this regard. The extracted liquid may beconcentrated to a level matching that of the original medicationsolution provided at the input of the nebulizer 110.

Liquid medication extracted from the expiratory pathway in the liquidcontainer 180 and refined using the above steps may be further directedto the nebulizer 110 via a return pathway 190, where it can be mixedwith the new liquid medication or combined into the aerosol mix createdtherein by other means. The newly created aerosol may then be directedback into the inspiratory pathway 120 for inhalation by the patient.

FIG. 2 shows a further embodiment of the invention in which an activeair pump 155 is added to the expiratory part of the circuit. The pump155 may be operated in a continuous mode, for example, as a centrifugalor another rotary air pump. This may be used to create a predefinedsuction level in the expiratory pathway so as to facilitate the movementof expiratory gases through that portion of the circuit. In otherembodiments, the air pump 155 may be a displacement pump, such as aperiodically expanded and collapsed bellows in one example. This type ofair pump may be operated asynchronously or, in other embodiments, insynchrony with the breathing rate of the patient by expanding during theexpiratory portion of the patient's breathing cycle. A further optionfor the active air pump 155 is to attach the expiratory portion of thebreathing circuit to the hospital vacuum system which may be adjusted tocreate a sufficient level of vacuum as to remove all expiratory gasessafely.

In further yet configuration of the circuit, a second air pump may beused on the inspiratory portion of the circuit and may be used to metera specific amount of aerosol-containing gas flow to reach the patient.

FIG. 3 shows yet another embodiment of the present invention in whichone or more sensors are provided in the expiratory or, in otherembodiments, in the inspiratory portion of the breathing circuit. Asseen in FIG. 3 , the first sensor 142 may be provided before thecondenser 150, and the second sensor 144 may be provided after thecondenser 150. The sensor may be a humidity sensor, in one example.Detection of a humidity level before and after the condenser 150 may beuseful in the determination of the total volume of liquid extracted fromthe gas flow. This information may then be used in calculating the totalvolume of consumed medication by the patient.

Another arrangement of the sensors may include color measurement of theinspiratory pathway and comparing that to the color measurement of theexpiratory pathway. If the liquid medication has a known color, thedifference in these measurements may further be used to estimate themedication consumption with greater precision as compared to the devicesof the prior art.

Additional sensors may also be featured at locations both before andafter the condenser 150, such as weight sensors, wavelengthdetermination sensors, spectrometer sensors, etc, as the invention isnot limited in this regard.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method of the invention, and viceversa. It will be also understood that particular embodiments describedherein are shown by way of illustration and not as limitations of theinvention. The principal features of this invention can be employed invarious embodiments without departing from the scope of the invention.Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thespecific procedures described herein. Such equivalents are considered tobe within the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference. Incorporation byreference is limited such that no subject matter is incorporated that iscontrary to the explicit disclosure herein, no claims included in thedocuments are incorporated by reference herein, and any definitionsprovided in the documents are not incorporated by reference hereinunless expressly included herein.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps. In embodiments of any of the compositions andmethods provided herein, “comprising” may be replaced with “consistingessentially of” or “consisting of”. As used herein, the phrase“consisting essentially of” requires the specified integer(s) or stepsas well as those that do not materially affect the character or functionof the claimed invention. As used herein, the term “consisting” is usedto indicate the presence of the recited integer (e.g., a feature, anelement, a characteristic, a property, a method/process step or alimitation) or group of integers (e.g., feature(s), element(s),characteristic(s), propertie(s), method/process steps or limitation(s))only.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, Aft AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, Aft BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

As used herein, words of approximation such as, without limitation,“about”, “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skilled in the art recognizethe modified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12, 15, 20 or 25%.

All of the devices and/or methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the devices and methods of this invention have beendescribed in terms of preferred embodiments, it will be apparent tothose of skill in the art that variations may be applied to the devicesand/or methods and in the steps or in the sequence of steps of themethod described herein without departing from the concept, spirit andscope of the invention. All such similar substitutes and modificationsapparent to those skilled in the art are deemed to be within the spirit,scope and concept of the invention as defined by the appended claims.

What is claimed is:
 1. A nebulizer gas scavenging system comprising: aninspiratory pathway leading to a facemask, and an expiratory pathwayleading from the facemask, wherein the inspiratory pathway furthercomprises a nebulizer with an input for a medical liquid, the nebulizeris configured to convert the medical liquid to an aerosol suitable forinhalation and to supply thereof through the inspiratory pathway to thefacemask, wherein the expiratory pathway further comprises a condenserconfigured to extract liquid from expiratory gases originating at thefacemask, wherein the expiratory pathway with the condenser therein isfurther configured to perform at least one of the following actions withthe extracted liquid: (i) sequester the fluid for subsequent disposal,(ii) determine at least one parameter of the extracted liquid, or (iii)direct the extracted liquid to the input of the nebulizer.
 2. Thenebulizer gas scavenging system as in claim 1, wherein the facemask isequipped with a one-way inlet valve attached to the inspiratory pathwayand configured to allow inhalation of the incoming aerosol, the facemaskis further equipped with a one-way outlet valve for directing exhaledexpiratory gases from the facemask to the expiratory pathway attachedthereto.
 3. The nebulizer gas scavenging system as in claim 1, whereinthe condenser comprises a convoluted, actively cooled flow pathway forexpiratory gases, the condenser further comprises a drain configured todirect the liquid extracted from the expiratory gases to a liquidcontainer, thereby separating the condensed liquid from expiratorygases.
 4. The nebulizer gas scavenging system as in claim 3, wherein thecondenser further comprises a vibration element coupled to a wall of theconvoluted pathway and configured to apply vibration thereto, therebycausing coalescence of liquid droplets to promote liquid drainagetherefrom.
 5. The nebulizer gas scavenging system as in claim 3, whereinthe convoluted pathway is removable from the condenser to allow cleaningand sterilization thereof.
 6. The nebulizer gas scavenging system as inclaim 3, wherein the condenser comprises a thermoelectric cooler using aPeltier effect.
 7. The nebulizer gas scavenging system as in claim 6,wherein the thermoelectric cooler comprises a cooling side thermallycoupled to the convoluted pathway of the condenser, the thermoelectriccooler further comprises a heater side configured to warm the medicalliquid of the nebulizer.
 8. The nebulizer gas scavenging system as inclaim 7, wherein the nebulizer, the condenser, and the thermoelectriccooler are integrated as a stand-alone self-contained device.
 9. Thenebulizer gas scavenging system as in claim 3 further comprising a drainpathway for directing liquid extracted from the expiratory gases by thecondenser to the liquid container.
 10. The nebulizer gas scavengingsystem as in claim 9, wherein the liquid container is configured to havean input from the drain pathway and an output in fluid communicationwith an input of the nebulizer.
 11. The nebulizer gas scavenging systemas in claim 10, wherein the liquid container is located below thecondenser so as to facilitate passive, gravity-controlled liquiddrainage from the condenser into the liquid container.
 12. The nebulizergas scavenging system as in claim 3, wherein the liquid container isconfigured for metering a volume or a weight of the incoming extractedliquid as a function of time, thereby enabling determination of theoverall consumption of the medical liquid inhaled from the nebulizersystem.
 13. The nebulizer gas scavenging system as in claim 3, whereinthe liquid container is configured for disinfecting the incomingextracted liquid.
 14. The nebulizer gas scavenging system as in claim13, wherein liquid disinfection at the liquid container is achieved byfiltering or exposing to a bactericidal UV light.
 15. The nebulizer gasscavenging system as in claim 3, wherein the liquid container is furtherconfigured for removal of water and increasing concentration of medicalliquid contained in the extracted liquid.
 16. The nebulizer gasscavenging system as in claim 15, wherein removal of water is done viawater evaporation or liquid centrifugation.
 17. The nebulizer gasscavenging system as in claim 3, wherein the expiratory pathway furthercomprises an air pump or configured for attachment to a hospital vacuumsystem to promote a flow of expiratory gases therein.
 18. The nebulizergas scavenging system as in claim 1 further comprising at least onesensor located in the expiratory pathway before or after the condenser.19. The nebulizer gas scavenging system as in claim 18, wherein the atleast one sensor is a humidity sensor.
 20. The nebulizer gas scavengingsystem as in claim 18, wherein the expiratory pathway comprises twosensors positioned before and after the condenser, the two sensors areconfigured to determine a total volume of liquid extracted from theexpiratory gases by the condenser.